Sepsis is a serious medical condition characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response to microbes in the blood, urine, lungs, skin, or other tissues. Sepsis is characterized by evidence of acute inflammation present throughout the entire body, and is, therefore, frequently associated with higher than normal heart rate, fever or lower than normal temperature and elevated white blood cell count (leukocytosis) or lower than normal white blood cell count.
The modern concept of sepsis is that the host's immune response to the infection causes most of the symptoms of sepsis, resulting in hemodynamic consequences and damage to organs. This host response has been termed systemic inflammatory response syndrome (SIRS) and is characterized by hemodynamic compromise and metabolic derangement. Outward physical symptoms of this response frequently include a high heart rate, high respiratory rate, elevated white blood cell count, and elevated or lowered body temperature. Sepsis is differentiated from SIRS by the presence of a pathogen. Without infection the above symptoms may not be classified as sepsis, only SIRS.
Severe sepsis occurs when sepsis leads to organ dysfunction, low blood pressure (hypotension), or insufficient blood flow (hypoperfusion) to one or more organs (causing, for example, lactic acidosis, decreased urine production, or altered mental status). Sepsis can lead to septic shock, multiple organ dysfunction syndrome (sometimes known as multiple organ failure) and death. Organ dysfunction may result from sepsis-induced hypotension and diffuse intravascular coagulation, among other things.
In the United States, sepsis is the second-leading cause of death in non-coronary intensive-care unit (ICU) patients, and the tenth-most-common cause of death overall according to data from the Centers for Disease Control and Prevention (the first being multiple organ failure). Sepsis is common and also more dangerous in elderly, immunocompromised, and critically-ill patients. It occurs in 1-2% of all hospitalizations and accounts for as much as 25% of ICU bed utilization. It is a major cause of death in intensive-care units worldwide, with mortality rates that currently range from 20% for sepsis to 40% for severe sepsis to >60% for septic shock.
Sepsis is usually treated in the intensive care unit with intravenous fluids and antibiotics. If fluid replacement is insufficient to maintain blood pressure, specific vasopressor drugs can be used. Artificial ventilation and dialysis may be needed to support the function of the lungs and kidneys, respectively. To guide therapy, a central venous catheter and an arterial catheter may be placed to monitor intravascular pressures. Sepsis patients require preventive measures for deep vein thrombosis, stress ulcers and pressure ulcers, unless other conditions prevent this. Some patients might benefit from tight control of blood sugar levels with insulin (targeting stress hyperglycemia), low-dose corticosteroids or activated drotrecogin alfa (recombinant protein C).
Presently there is great variability in the diagnosis and management of sepsis generally across health care institutions, between and among physicians, and between and among differing patients, even within the same health care institution. Additionally, mortality and cost of intensive care unit (ICU) care of patients with sepsis remain prohibitive. To apply current standard of care to sepsis patients typically requires frequent or constant bedside presence of an expert physician to guide decision making for monitoring or therapeutic interventions. Available evidence based guideline and other literature evidence for management of sepsis are difficult for the bedside clinician to use to direct the care process for the individual patient, and ad hoc treatment with haphazard application of literature evidence or guideline recommendations is common.
Consequently, it is desired to substantially ameliorate these problems.